The effects of phospholipase A (PLA) and phospholipase C (PLC) on bioelectrically excitable tissues have been extensively studied in order to probe the function and structure of membranal phospholipids. In contrast, phospholipase B (PLB; lysophospholipase) has not been studied due to the lack of availability of large amounts of purified enzyme. We have unique access to the oriental hornet venom, which is very rich in PLA and PLB activities. The effects of hornet venom and its located PL will be studied on the following: Central Nervous System (CNS) of Rat - convulsant action following intraventricular injection, binding of gamma-aminobutyric acid (GABA) to junctional complexes, uptake of GABA into synaptosomes, release of lysosomal enzymes. Squid Giant Axon - action and resting potential, permeability, release of free amino acids, ultrastructual changes. Isolated Single Electroplax - directly and indirectly evoked action potential, resting potential, caabamylcholie depolarization, ultrastructural changes. The extent of hydrolysis of each phospholipid in the tissues of interest will be related to biological effects. The experiments should help clarify the mechanism(s) of convulsions induced by exogenous PL and the role of endogenous PL in convulsive states; essentiality of PL activity of pre-synaptically active animal toxins; effect of disruption of hydrophobic bonding by PLA plus PLB on permeability and ultrastructure of biological membranes; contribution of PL to the pharmacological actions of the oriental hornet venom. This hornet has recently been inadvertently introduced into the United States and may become a severe pest.